The Institute's work has several roots. A central one is Psychosynthesis. First formulated in 1910 by the Italian psychiatrist Roberto Assagioli and gradually developed over the last eighty-five years in Europe and North America, Psychosynthesis is based on principles that can be used to understand, and work with, both the micro-dynamics of individual development and the macro-dynamics of social evolution. It draws on both eastern and western thought to describe the process by which the Spiritual Self gradually develops, re-organizes, heals, and eventually infuses the personality and personal/social life. Other roots include the fields of Existential, Humanistic, and Transpersonal Psychology, Psychoanalytic and Analytic Psychology, Systems Theory, Eastern Spiritual Psychologies, particularly Buddhism, and teachings from traditional cultures, particularly the Native American.
These roots nourish an evolving theory and practice of Spiritual Psychology. Spiritual Psychology delineates a common human process of psycho-spiritual development, the principles by which it proceeds, and practices that are useful in supporting this process. It embraces the various dimensions of human experience-physical, psychological, spiritual, social- and studies their interplay as it affects development and transformation at individual, group, organizational, and planetary levels. Different Institute programs/services focus on different levels, but all stem from a growing body of theory and practice which honors and includes the spiritual dimension as central to human existence, healing, and growth.